@urbankitstudio/atlas

JS SDK for the UrbanKit County Parcel REST API Atlas — a curated index of public ArcGIS REST endpoints for US county parcel data, with searchable field metadata, sample queries, and license info.

Use it to:

• Look up the parcel REST endpoint for a given US county (e.g. Kane County, IL).
• Discover which fields are searchable on each endpoint (PIN, owner name, address).
• Build deep-links into the UrbanKit parcel lookup tool.

The data is the same set powering urbankitstudio.com/parcel-atlas, bundled offline so your code does not need to make a runtime network request.

Install

npm i @urbankitstudio/atlas

Works in Node.js (>=18) and modern bundlers (Vite, webpack, esbuild, Rollup, Next.js, Remix). Ships ESM + CJS with full TypeScript types. No runtime dependencies. sideEffects: false.

Quick start

1. List populated states

import { listStates } from "@urbankitstudio/atlas";

const populated = listStates().filter((s) => s.populated);
// [{ slug: "arizona", name: "Arizona", abbrev: "AZ", countyCount: 1, ... }, ...]

2. Look up a county by slug

import { findCounty } from "@urbankitstudio/atlas";

const kane = findCounty("illinois", "kane-county");
if (kane) {
  console.log(kane.endpoints[0].url);
  // → https://gis.kanecountyil.gov/...

  const pin = kane.endpoints[0].searchFields.find((f) => f.name === "PIN");
  console.log(pin?.label);
  // → "Parcel Identification Number (PIN)"
}

3. Look up a county by FIPS code

import { findCountyByFips } from "@urbankitstudio/atlas";

const kane = findCountyByFips("17089"); // 5-digit county FIPS (state + county)
if (kane) {
  console.log(kane.county, kane.stateSlug);
  // → Kane illinois
}
// Unknown, malformed, or non-5-digit input returns undefined (never throws).

4. Build a parcel-lookup deep-link

import { findCounty, buildParcelLookupDeepLink } from "@urbankitstudio/atlas";

const kane = findCounty("illinois", "kane-county")!;
const link = buildParcelLookupDeepLink(kane.endpoints[0]);
// → https://urbankitstudio.com/tools/parcel-lookup?endpoint=https%3A%2F%2F...&fieldHint=TaxName

For single-address owner lookups in the browser, the free [Owner Lookup](https://urbankitstudio.com/tools/owner-lookup) tool reads the same county layers this package indexes.

API

| Function | Returns | |---|---| | listStates() | StateIndexEntry[] — all 50 states and DC + populated flag | | findState(stateSlug) | StateFile \| undefined | | findCounty(stateSlug, countySlug) | CountyRecord \| undefined | | findCountyByFips(fips) | CountyRecord \| undefined — match by 5-digit county FIPS | | listCountiesByState(stateSlug) | CountyRecord[] | | buildParcelLookupDeepLink(endpoint) | URL string into the UrbanKit lookup tool | | slugify(s), countySlugFromName(s) | string helpers matching the atlas slug convention | | statePath(slug), countyPath(state, county) | URL paths under /parcel-atlas |

The full typed root is also exported as atlas:

import { atlas } from "@urbankitstudio/atlas";

atlas.version;          // string
atlas.lastUpdated;      // ISO date
atlas.totals;           // { states, counties, endpoints }
atlas.byStateSlug;      // Map<stateSlug, StateFile>

status is a publish-time claim, not a live signal

This package ships static JSON and makes no network calls, so status and lastVerified on every endpoint describe what was true when the version you installed was published. status: "live" means a check passed before publish — not that the endpoint is up right now. A county can go down the day after a release and every installed copy keeps saying "live" until the next one.

The distinction is not hypothetical: on 2026-08-04 a county was being served as "live" from its registry entry while the liveness probe had it down that same afternoon.

For the current answer, ask the health endpoint — no API key, refreshed every two hours:

import { LIVE_STATUS_URL } from "@urbankitstudio/atlas";

const res = await fetch(`${LIVE_STATUS_URL}?fips=17089`);
const health = await res.json();
// { ok: true, found: true, county_fips: "17089",
//   status: "ok" | "degraded" | "down" | "unknown",
//   consecutive_failures, last_ok_at, checked_at }

Two cases to handle rather than ignore:

• found: false means no observation exists — the county may be untracked or never probed. It is not a statement that the endpoint is healthy.
• A 503 means the health store itself was unreachable. Also not a health claim.

Treat both as unknown. Neither should render as "up".

Omit ?fips= to get every tracked county in one call.

Coverage today

The atlas bundles 235 counties across all 50 US states and DC (247 verified endpoints), covering the largest counties in each. Call listStates() to enumerate the full set.

Every state has at least one county on record, and 229 of the 235 carry a verified endpoint. The other 6 have hasPublicRest: false and an empty endpoints array, with notes recording the reason and who to contact. Those reasons vary: a subscription-only regional GIS partner, a statewide server that requires an auth token, a state with no county-level parcel authority, a county viewer with no public query API, a county that does not publish owner names online. They ship rather than being omitted, so findCounty() still resolves them. Check hasPublicRest rather than assuming every county has an endpoint; totals.countiesWithEndpoint gives the queryable count directly.

Counties are added as their public REST endpoints are verified. Package versions bump when data refreshes — pin to a minor range (^0.x) to receive new counties without breaking changes.

The live, browseable atlas lives at urbankitstudio.com/parcel-atlas.

Socket flags urlStrings — that's the atlas, not a leak

Socket's supply-chain scanner flags this package for urlStrings: code and data containing many literal URLs. That flag is doing its job correctly, and the answer is not to hide the URLs — they are the product. Every one is a public, government-run ArcGIS REST endpoint for county parcel data, plus the two urbankitstudio.com URLs this SDK references for live status (LIVE_STATUS_URL, above) and parcel-lookup deep links. The package does not call any of them itself; it hands them to you as data (sideEffects: false, zero runtime dependencies).

Socket also flags unpopularPackage — a download-count signal, not a code issue, that install growth resolves on its own.

License

MIT — see LICENSE. © 2026 UrbanKit Studio.

This package's atlas dataset (the open discovery layer — county → REST endpoint mappings and field metadata) is provided under MIT. Live, always-fresh and enriched data — geocoding, address→parcel resolution, bulk enrichment, and the data-availability SLA — are the paid UrbanKit Studio API.